1. Field of the Invention
The invention relates generally to the field of brake systems for aircraft. More specifically, the invention relates to the establishment of redundancy in aircraft brake systems.
2. Description of the Related Art
Historically, aircraft braking systems initially involved the use of a brake pedal in the cockpit of an aircraft, and a mechanical system being directly linked between the pedal, and the brakes at the aircraft wheels. Some more-modern systems include a fly-by-wire arrangement. Fly-by-wire braking systems use positional sensors to determine the position of the brake pedal, and then apply or release the brakes based on sensed pedal position.
Most modern aircraft also include one or more brake modules that receive the sensed pedal information, and use a valved hydraulic system to introduce fluid pressure into chambers at each brake to activate each brake. Information received by the modules from pressure sensors near each brake is used to make sure that appropriate brake pressure to be applied hydraulically in a uniform fashion.
Dual-channel brake control systems are common in the industry. These systems, however, include dual-channel arrangements. More specifically, the controller is divided such that each channel controls one half of the brakes independently. Thus, both control channels are always active during normal operation. In these systems, if one channel fails, then only one half of the brakes remain available.
A dual chamber brake is also currently used in industry. But with these systems, the dual chamber brake is divided such that one half of the brake pistons are controlled by one brake system and the remaining half by another brake system. Both brake systems and therefore all the brake pistons are used during normal operation. And if one of the two brake systems fail, then only one half of the brake pistons are used. Normal stopping performance requires all the brake pistons to be operational. Thus, the failure will result in less stopping power.